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Biomedical subjects

H Leonhardt

Publications and source records attributed to H Leonhardt.

At least 91 records · Page 5Linked to original sources
PubMed1978

[Peritoneoscopic diagnosis of M. Whipple--making an indirect diagnosis (author's transl)].

A case report is given of a patient with a malabsorption syndrome. Primary diagnostic procedures including x-ray examinations and endoscopy yielded no results. Alterations of the abdominal lymph vessel system were found during peritoneoscopy giving rise to the hypothetical diagnosis of Whipple's disease. This diagnosis was confirmed by intestinal biopsy yielding macrophages with PAS-positive inclusion bodies. It is pointed out, that peritoneoscopy is a good means to evaluate the abdominal lymph vessel system.

Doxycycline↗
PubMed1977

[Methodical investigations concerning the measurement of red cell deformability dependent on plasma viscosity, plasma proteins, hematokrit, filtration pressure as well as osmolarity (author's transl)].

The measurement of red cell deformability (flexibility or fluidity) according to the method of filtration strongly depends on the suspension medium, the hematokrit, filtration pressure as well as osmolarity and is hard to differentiate over the influence of red cell aggregation. Therefore, data concerning the flexibility of red cells have to be established under standardized conditions, e.g. suspension medium, such as albumin, stabilized hematokrit, constant osmolarity and pressure.

Blood↗
PubMed1977

Lipids in the proximal convoluted tubule of the cat kidney and the reabsorption of cholesterol.

Lipid deposits in the cat kidney are mainly located in the epithelium of the proximal tubuli contorti, particularly in the pars contorta. As the amount of fatty acids in the blood of renal arteries is higher than in renal veins, the lipid inclusions are likely to be formed in the proximal convoluted tubule. Whether fat occurring in the urine has been released from the nephron epithelium and the mode of this release remains obscure. The structural equivalent of lipid extrusion into the tubules has not been observed. Components of the tubular lipids include triglycerides, phosphoglycerides and cholesterol. The results of the digitonin-cholesterol reaction favour the assumption that cholesterol is eliminated in the glomeruli and pinocytotically reabsorbed by the brush border cells, this process possibly serving recycling of this compound. The dilated basal labyrinth and intercellular space contain perpendicularly oriented lipid accumulations that reach the basal lamina. The ultrastructure of the lipid storing cells of pars contorta reacting positively for phosphoglyceride and cholesterol is characterised mainly by bodies with marginal plates. As far as can be judged from their morphology, these bodies are interpreted as large peroxisomes. A special feature of the pars recta are dumbbell shaped bodies and elongated or cup-like mitochondria concentrically surrounding cytoplasmic areas, as well as a well-developed smooth ER. In what way the organelles of the brush border cells are involved in catabolic and anabolic processes as far as renal lipid metabolism is concerned remains to be answered.

Animals↗
PubMed1977

Effects of pentoxifylline on red blood cell deformability and blood viscosity under hyperosmolar conditions.

Using a hyperosmolar erythrocyte model, the authors studied the effect of changes in red cell deformability on whole blood viscosity and investigated the possibility of using pentoxifylline to modify red cell deformability and whole blood viscosity. In vitro studies reveal a significant correlation between the two parameters in as much as they are inversely proportionate, i.e. viscosity increases as red cell deformability decreases and vice versa. Addition of pentoxyfylline improves impaired red cell deformability under hyperosmolar conditions and simultaneously produces a reduction in whole blood viscosity.

Blood Viscosity↗
PubMed1977

Studies of plasma viscosity in primary hyperlipoproteinaemia.

Using an Ubbelohde capillary viscometer, viscosity was determined in the plasma of 39 patients with a primary hyperlipoproteinaemia (type IIa, n=13; type IV, n=12; type IIb, n=14), in isolated lipoprotein fractions as well as in sera which differed only in their lipoprotein concentration. Plasma viscosity of the patients with hyperlipoproteinaemia was compared to that of a normolipidaemic control group and correlated with the lipid fractions characteristic of the different hyperlipoproteinaemia types. Plasma viscosity in types IIa, IV and IIb was found to be significantly higher than in the control group. Of the different hyperlipoproteinaemia types, IIa exhibited the lowest and IIb the highest plasma viscosity levels. The elevation of plasma viscosity was correlated with the concentration of lipoproteins (lipid fractions). In viscosity measurements of sera which varied only in lipoprotein concentrations, a correlation between the increase of viscosity and lipoprotein concentration as well as a greater efficiency of VLDL fractions was observed, similar to the viscosity results from isolated lipoproteins.

Adult↗
PubMed1977

Effects of thymectomy on the endocrine glands of the rat.

The effects of thymectomy on the thyroid gland, the adrenal cortex, the testes and the lymph nodes of the rat follow the same pattern as those observed in guinea pigs but in a very attenuated form. Thymectomized rats do not show the wasting observed in thymectomized guinea pigs. The effects on the adenohypophysis are approximately the same in rats and guinea pigs, but the sequence of the changes is different. Injections of thymic extract or of presumably pure thymic hormone suppressed all the effects of thymectomy on the endocrine glands of the rat. In rats, thymic hormone was found in the thymus, the lymph nodes and the spleen. It disappeared from the lymph nodes and the spleen within three days of thymectomy and did not reappear, although most of the changes in the endocrine glands were transitory. The implications of the observations for understanding the consequences of thymectomy are discussed.

Adrenal Cortex↗
PubMed1976

"Axonal spheroids" in the spinal cord of normal rabbits.

Within the gray matter and the white matter of the spinal cord of apparently healthy rabbits, myelinated and unmyelinated axonal swellings, so callled "xonal spheroids", occur. Most of the spheroids contain mitochondria, dense bodies, vesicles and fragments of the tubular or smooth endoplasmic reticulum. In myelinated spheroids the process of swelling is effected by slippage of the myelin leaflets. At the periphery of the unmyelinated parts of the spheroids, synapses are regularly found. The presynpatic terminal bouton is formed by the spheroid. A few myelinated and unmyelinated spheroids are packed with fine granular material while mitochondria are lacking. The axonal spheroids may represent a physiological, perhaps agedependent phenomenon.

Aging↗
PubMed1976

[The cerebrospinal fluid contact processes in the central canal of the spinal cord. A scanning and transmission electron microscopic study of the rabbit].

The surface of the central canal of the rabbit spinal cord was investigated with scanning and transmission-electron microscopy. On the ventral wall of the central canal, a long cranio-caudally oriented area carries a row of bulbs (about 630 per millimeter of length). The bulbs are spinal ventricular processes of cerebrospinal fluid contacting nerve cells. Its cytoplasm contains mitochondria, smooth- and rough-surfaced endoplasmic reticulum and vesicles of various size and contents. The bipolar or multipolar nerve cells are situated below the ependymal cells of the central canal. The perikaryon has the general cytological structure of a neuron. Some nerve fibres are shown to be running in the cranio-caudal direction within the central canal. Axons containing synaptic vesicles (diameter 400 A) form synapses on some of the ventricular processes. Two main types of ventricular processes can be observed, they differ in the size and structure of the end bulb, in the shape of its sterocilia, and in the number of mitochondria. Big globular processes are filled with a great number of mitochondria, whereas stereocilia are lacking. On the contrary, small processes with numerous stereocilia extending radially into the cerebrospinal fluid contain a number of mitochondria. A third type takes the mid position between the two main types. The ventricular processes have no "sensory cilia". On the basis of these morphological differences the possible role of mitochondrial movements in the function of the ventricular processes and the question of the identity of the three types of processes are discussed.

Animals↗
PubMed1976

[Connective tissue in the perivascular spaces of subependymal capillaries of the spinal cord in the rabbit].

The normal structure of the subependymal capillaries and venules of the spinal cord was studied in rabbit. The endothelial cells of the capillaries and venules are surrounded by an irregularly formed perivascular space, about 0.5 to 3.3 micrometer wide, which is delimited by an endothelial and glial basal lamina. The space contains a framework of collagen fibers. A period-acid-bisulfit-aldehydthionine-method (Specht) permits to find the perivascular connective tissue lightmicroscopically, while they can be identified by electron microscopy. The significance of the perivascular connective tissue is open to discussion. Structural and functional problems have been reviewed in this context.

Animals↗
PubMed1975

[Alterations in blood- and plasma-viscosity of patients with risk-factors (author's transl)].

In a series of tests, performed on patients with the risk-factors smoker and adiposity, a comparison with normal persons revealed a statistically significant hyperviscosity in plasma and whole blood for smokers and overweight patients. When both risk-factors occurred simultaneously, the blood- and plasma-viscosity displayed a distinctly additive increase. Furthermore, female patients taking contraceptives showed a significantly increased plasma- and blood-viscosity when comparing them with a group of normal persons. In a group of pregnant women, hyperviscosity could not be secured statistically.

Adult↗
PubMed1975

[Investigations on the Influence of Thrombocytes and Temperature on the Whole Blood- and Plasma-Viscosity as Comparative Measurements Between a Capillary- and a Plate-Cone-Viscosimeter (author's transl)].

The capillary viscosimeter (Viscotimer) tested with different Ubbelohde-viscosimeters is suitable for measurements of plasmaviscosity; the limitting factor of the measuring method is the exact adjustment of the temperature. When testing the plate-cone-viscosimeter (Wells-Brookfield Microviscosimeter), we achieved scientifically adequate results only when using shear rates 230, 115 and 46 sec-1. An influence of different thrombocyte-concentrations on the viscosity of whole blood and plasma could not be detected. The flow capacity of whole blood and plasma is distinctly dependent on the temperature.

Blood Platelets↗
PubMed1975

[Changes of blood-flow properties in patients with chronic liver disease (author's transl)].

The determination of plasma viscosity in 37 patients with liver disease allowed their subdivision into three groups. Firstly, decreased viscosity (hypoviscosity) was found in patients with cirrhosis, marked portal hypertension and esophageal varices. Secondly, normal viscosity (normoviscosity) was found in patients with inactive cirrhosis without portal hypertension, and thirdly, increased viscosity (hyperviscosity) was found in patients with active cirrhosis and chronic progressive hepatitis. The concentrations of total serum protein, of fibrinogen and of IgG were found to influence plasma viscosity. A detailed differentiation revealed that increased plasma viscosity is caused by increased levels of IgG while decreased viscosity correlates with low fibrinogen levels. Furthermore a close correlation exists between plasma viscosity and the enzymatic activity of SGOT, SGPT and GLDH. In 5 patients with chronic progressive hepatitis treated with corticosteroids the plasma viscosity normalized in parallel with improvement of the hepato-cellular damage. These findings will be discussed in detail. Hyperviscosity might possibly serve as an additional parameter to characterize chronic progressive hepatitis and to indicate steroid treatment.

Alanine Transaminase↗
PubMed1975

Influence of the thymus-corticothropin-growth hormone interaction on the rejection of skin allografts in the rat.

Skin allograft rejection was noticeably delayed in rats following hypophysectomy. Daily injections of hypophyseal growth hormone restored the normal reaction. Additional thymectomy had no influence on the rejection of hypophysectomized rats. In these animals growth hormone by itself had no significant influence on the graft rejection. It only restored a normal reaction when given together with thymic hormone. Corticotropin injections accelerated the allograft rejection. On this action of corticotropin thymic hormone has shown a significant inhibitory influence. The thymus was thus proved to be a synergist to growth hormone and an antagonist to corticotropin. Previous observations made with usual endocrinological test- are thus confirmed with an immunological test.

Adrenocorticotropic Hormone↗
PubMed1975

Recent observations on ependyma and subependymal basement membranes.

Directly under the ependyma, and between the ependymal cells, there are basement membranes which form labyrinths connecting with the perivascular basement membranes of the subependymal vessels. The basement membranes exhibit differences in form, position, and distribution, and they can be distended by fluid absorption into large lacunae. The membranes can be identified as glycoprotein and glylcolipid substances. Electron microscopic studies have shown the differences between the basement membrane labyrinths of the human, the rabbit and the rat. In the human, the labyrinths contain isolated collagen fibrils. Basement membranes generally line all connective tissue spaces and form their interstitial borders. From this point of view, the subependymal basement membrane labyrinths can be seen as interstitial spaces near the ventricles, forming pathways between the ependyma and the subependymal capillaries or postcapillary veins.

Animals↗